This study will evaluate the safety and effectiveness of oxcarbazepine (Trileptal) as add-on therapy in the treatment of partial seizures in pediatric patients 1 month to 3 years of age.

INCLUSION CRITERIA: To enter this study, patients must:

• Have a diagnosis of partial seizures
• Be willing to be hospitalized
• Weigh a minimum of 6.6 pounds
• Be taking a stable dose of one to two concomitant anti-epileptic medications
• Have had a previous CAT scan/MRI confirming the absence of space occupying lesions or progressive neurological disease
• Have normal laboratory results

EXCLUSION CRITERIA: To enter this study, a patient must not have or be:

• Seizures caused by metabolic disturbance, toxic exposure, or active infection
• A primary diagnosis of generalized epilepsy (exception - secondarily generalized seizures)
• A history of status epilepticus within 30 days
• Seizures not related to epilepsy
• Frequent use of additional anti-epileptic medications to treat increases in seizures (for example: rectal diazepam)
• Taking felbamate within 6 months
• Serum sodium levels <135 mEq/L
• Significant heart, breathing, kidney, stomach, liver, blood, or cancer disorder requiring treatment/therapy
• A history of chronic infection (e.g., hepatitis or HIV)
• Significant electrocardiogram (ECG) abnormalities
• A nursing mother taking anti-convulsant drugs
• Previously demonstrated sensitivity/allergic reaction to Trileptal or related compounds
• Used experimental medication within 30 days of entering this study